Originally Posted by cHarley

I won't even get into how bad the life expectancy is on most oil-less compressors.

But if you're looking to use air driven tools, especially continuously driven tools like buffers & grinders, you'll want a 20+ gal tank ( the bigger the better) and a compressor that will do at least 4.5 scfm @ 90 lbs as a minimum.

My oil-type compressor is 30+ yo and still going strong.